In view of escalating fuel prices and particularly natural gas prices, there has been a resurgence in the need to consider less costly fuel options.
One of the limitations in the fuel generation art is that the art has not thoroughly considered the possibility of using materials which are generally not considered as fuels, but have the possibility of conversion to useful fuel. One such material that is useful is residuum and in particular, heavy oil residuum. Such materials present numerous difficulties in that the viscosity is quite high to the point that the material almost comprises a solid and thus handling and conversion to a form suitable for use as a combustible fuel have presented difficulties. It is known in the chemical engineering field that droplet size range is important to produce a fuel which will burn in a host of boiler types and not present problems in terms of boiler selection, sufficient carbon burnout or violation of existing flue gas opacity standards.
It has been proposed previously to convert other materials to a fuel, however, such proposals have not proved viable, since droplet size could not be produced in a size distribution sufficient to be efficiently burned in a wide variety of boilers or other combustion devices.
In U.S. Pat. No. 5,551,956, issued to Moriyama et al., Sep. 3, 1996, there is disclosed a super heavy oil emulsion fuel and method for generating deteriorated oil and water super heavy oil emulsion fuel. The fuel is indicated to have a relatively low viscosity and adequate long-term stability and comprises in an emulsified state 100 parts by weight of a super heavy oil, 25 to 80 parts by weight water and 0.02 to 5 parts by weight of the non-ionic surfactant. This reference teaches a useful fuel, however, there is no recognition of formulating an emulsion which creates a particle size sufficient for use as an energy source in a boiler for use in power generation and steam recovery for heavy oil recovery.
Ichinose et al., in U.S. Pat. No. 6,036,473, issued Mar. 14, 2000, teaches a heavy oil emulsified fuel combustion apparatus. This reference is primarily focused on the apparatus and does not go into any real detail with respect to a fuel or conversion process for converting residuum to a useful combustible fuel.
U.S. Pat. No. 6,001,886, issued to Shirodkar, Dec. 14, 1999, teaches an asphalt emulsion formation process. The process involves preheating the asphalt residue for combination with emulsifier with subsequent mixture to a homomixer. The temperature is relatively low at 38° C. in order to prevent interference in the emulsification. This is reflected in the Patentee's comments concerning the importance of not exceeding 100° C. to prevent dehydration of the emulsion.
Bando, in U.S. Pat. No. 6,183,629, issued Feb. 6, 2001, sets forth an emulsion formulating apparatus for formulating liquid/solid emulsions. The emulsions formed with the apparatus have a wide particle distribution as opposed to a specific distribution required for combustion. By the Bando device, it would appear that the arrangement is specifically designed for fluid (liquid/solid) emulsion transport instead of liquid/liquid emulsion combustion.
It would be desirable if there were a method to formulate a combustible fuel in a desirable size range for the emulsified particles to be used in any type of boiler for use as an energy source. The present invention speaks to the issues in the industry and presents a particle having a droplet size necessary to achieve more efficient burning.